Communication for distributed control of slotcar vehicular platoon

55 Pages·2015·12.12 MB·English

by  Anastasia Vlasova

bachelor’s thesis
Communication for distributed control of
slotcar vehicular platoon
Anastasia Vlasova
May 2015
Supervisor: Herman Ivo Ing.
Czech Technical University in Prague
Faculty of Electrical Engineering, Department of Control
Engineering

Abstract
This research focuses on the preparing of the inter-vehicles communication system for
the slotcar platoon model. The communication is implemented as a feed-forward signal
and improves the existing cascade feedback controller, which uses only the onboard
sensors measurements. The slotcar platoon model consists of three slotcars provided
by Carrera. Each vehicle is equipped with ARM Microcontroller and radio board with
CC2530 wireless MCU which runs full ZigBee Pro solution. This thesis also deals
with the ZigBee network processor configuration and contains the description of the
ZigBee hardware driver implementation. Being equipped by wireless communication
capabilities slotcars communicate with each other and the base station. It allows to
control vehicles wirelessly, read out data during the experiments and identify car’s
position in the platoon.
Keywords
ZigBee; CC2530; CC2530ZNP-Pro; STM32F4; SPI; radio board; slotcar; cognitive
vehicle platooning; CACC; position identification...
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Abstract
Tento dokument ze zabývá implementací bezdrátové komunikace mezi autodráhovými
autíčky. Tato komunikace je použita pro implementaci dopředného řízení, o které je
rozšířen již implementovaný zpětnovazební kaskádní regulátor vzdálenosti, používající
pouze veličiny měřené lokálními senzory na autíčku. Každé autíčko je vybaveno ARM
procesorem a komunikačním čipem CC2530, poskytující ZigBee Pro standard. Tato
práce se také zabývá samotnou konfigurací a popisem tohoto čipu. Použitím bezdrátové
komunikace jsou autíčka schopna posílat data během experimentu do počítače. To
umožnuje bezdrátové ovládání kolony, konfiguraci parametrů a určení pořadí autíček.
Klíčová slova
ZigBee; CC2530; CC2530ZNP-Pro; STM32F4; SPI; radio board; slotcar; CACC; určení
pozice...
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Contents
1 Introduction 1
1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 The Slotcar platooning project . . . . . . . . . . . . . . . . . . . . . . . 2
2 CC2530 communication processor 3
2.1 The secondary radio board implementation . . . . . . . . . . . . . . . . 3
2.2 Prototype model for the ZigBee driver development. . . . . . . . . . . . 4
CC2530 ZigBee Development Kit . . . . . . . . . . . . . . . . . . 4
STM32F401C-DISCO . . . . . . . . . . . . . . . . . . . . . . . . 5
3 ZigBee standard specification 7
3.1 The ZigBee base: IEEE 802.15.4 . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Interaction between the ZNP and the application processor . . . . . . . 9
3.2.1 Initializing SPI . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
STM32F4 External interrupts . . . . . . . . . . . . . . . . . . . . 11
3.3 CC2530-ZNP power-up procedure . . . . . . . . . . . . . . . . . . . . . . 11
3.4 CC2530-ZNP startup procedure . . . . . . . . . . . . . . . . . . . . . . . 12
Network formation . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Network Discovery/Join . . . . . . . . . . . . . . . . . . . . . . . 16
Data Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
The data path in NWK layer . . . . . . . . . . . . . . . . . . . . 18
3.4.1 ZigBee addressing . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4 Communication infrastructure 21
4.1 The ZNP driver implementation . . . . . . . . . . . . . . . . . . . . . . 21
4.2 Main program layer services . . . . . . . . . . . . . . . . . . . . . . . . . 23
Register leader . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Send address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Slot-car parameters configuration . . . . . . . . . . . . . . . . . . 24
Position determination . . . . . . . . . . . . . . . . . . . . . . . . 25
Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5 Experiments 30
5.1 The regulation model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.2 Experiments’ results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.2.1 Distance error . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Technical problems . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.2.2 Future work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
6 Conclusion 36
Appendices
A Hardware specifications 37
B ZigBee Interface parameters 39
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C Commands for CC2530-ZNP configuration 41
C.1 Power-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
C.1.1 System state after reset (POLL) . . . . . . . . . . . . . . . . . . 41
C.1.2 The device startup options configuration (SREQ) . . . . . . . . . 41
C.2 Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
C.2.1 Channel (SREQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
C.2.2 Device logical role (SREQ) . . . . . . . . . . . . . . . . . . . . . 42
C.2.3 PAN ID (SREQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
C.2.4 Simple Descriptor (SREQ). Application profile and endpoint . . 42
C.2.5 Start device in the network (SREQ) . . . . . . . . . . . . . . . . 43
C.2.6 Device status (POLL) . . . . . . . . . . . . . . . . . . . . . . . . 43
C.3 Transmit data (SREQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
C.4 Receive Data (POLL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
C.5 Get device information (SREQ) . . . . . . . . . . . . . . . . . . . . . . . 44
D The attached CD content 45
Bibliography 46
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Abbreviations
Abbreviation Phrase
AP Application Processor
API Application Programming Interface
APL Application layer
CCA Clear Channel Assessment
CRC Cyclic Redundancy Code
CSMA-CA Carrier Sense Multiple Access - Collision Avoidance
EM Evaluation Model
FCS Frame Check Sequence
FFD Full-Function Device
GTS Guarantee Time Slots
HW Hardware layer
MAC Medium Access Control layer
MCU Microcontroller Unit
MHL Message Handler Layer
MPL Message Program Layer
NWK Network layer
PAN Personal Area Network
PHY Physical layer
RF IC Radio Frequency Integrated Circuit
RFD Reduced-Function Device
SPI Serial Peripheral Interface
ZC ZigBee Coordinator
ZDK ZigBee Development Kit
ZDO ZigBee Device Object
ZED ZigBee End Device
ZHA ZigBee Home Automation
ZNP ZigBee Network Processor
ZR ZigBee Router
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1 Introduction
Themaingoaloftheprojectistoimplementacommunicationinfrastructureforplatoon
control algorithms, in which vehicles share their states with the others. To do it we
need to choose a suitable communication standard and implement the solution into the
slotcar. This thesis describes the implementation process, which includes the study of
thevehiclehardwareandsoftware,theSPIinitialization,detailedresearchontheZigBee
communication standard and creating the ZigBee hardware driver which provides the
transmissionandreceptionservices. Differentalgorithmswereimplementedinthemain
program layer as well, e.g. position determination in the platoon, address information
or parameters setting.
1.1 Motivation
The Super Smart Vehicle System(SSVS) was created to make multiple improvements
such as the following: reduce car accidents, optimize speed and handling, increase fuel
efficiency and prevent traffic jams. The SSVS was introduced by JSK (Association of
Electronic Technology for Automobile Traffic and Driving) in Japan in 1990 [1]. The
SSVS consists of 4 fields: information systems for a single vehicle, information systems
for inter-vehicles, information systems for vehicle-to-road relations, and studies on
vehicle-to-driver relations [2].
Figure 1. Autonomous Vehicle Design (Source: www.nuvation.com)
One of the main goals of this work is to extend the already existing slotcar platoon
model [3] to the "cognitive vehicles platooning", where vehicles are coupled together
by wireless communication. Previous works were focused on creating the controllers to
follow the reference distance and speed based only on sensor measurements. Using the
precedingortheleadingvehiclemeasurementsinacombinedfeedbackandfeed-forward
loop improves the response to the preceding car and minimizes the control signal value.
The motivation was not only to improve the existing platform, but try different
algorithms on it which could hardly be realized without data exchange. For example,
car’s position identification in the platoon.
1
1 Introduction
Through the course of this research project further knowledge about microcontrollers
and communication protocols (especially ZigBee) was gained.
1.2 The Slotcar platooning project
This project was started in the Department of Control Engineering by the AA4CC
group[3]. The goal of this work is to create a slotcar platoon model for testing
distributed control algorithms on it.
The main part of the system is a slotcar by Carrera. It is equipped with custom-made
electronics. The following are the most important components placed on the main
board:
∙ ARM processor by ST Microelectronics STM32F405RGT6,
∙ debug communication processor Nordic Semiconductor nRF24L01,
∙ gyro with integrated accelerometer LSM330DLC,
∙ INA213AIDCKT current-shunt monitor,
∙ QRE1113 reflective object sensor is used for speed measurements.
. A VEMT3700F silicon NPN phototransistor and a VSML3710 infrared emitter are
placed on the distance measurement board. There are two such boards in the slotcar:
for back and front distance measurements. On the separate board is located the ZigBee
CC2530 communication processor. The hardware design and implementation was done
by Ing. Jaromír Dvořák.
Figure 2. The slotcar with the secondary ZigBee radio board
The project is being developed in Eclipse CDT (C/C++ Development Tooling) [4].
In the project are used the ARM Cortex Microcontroller libraries. Jaromír Dvořák
wrote the basic program, system functions and the Bootloader program to load the
compiled code into the chosen slotcar. After the run of the project the program asks
for the ‘car address’, which is a number from 1 to 10 written on the vehicle. For loading
Nordic nRF51-Dongle is used. The slotcar bond graph modeling, identification and
linearization were done by Martin Lád [5]. He also designed and implemented two
speed measuring methods (by IRC sensor and back emf) and speed regulator. One of
the main achievements was enabling of regulation of low speeds such as 200𝑚𝑚·𝑠−1.
The creation of the distance measuring sensor is described in the thesis of Jan Moravec
[6]. There are shown results of testing distance control algorithms on the car platoon.
Results of the current project were tested with the android application, which was
written by Alexander Dubeň. A more detailed description of provided experiments are
placed in the final chapter.
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